Dreams featuring contrasting colors and shapes can often symbolize a clash of emotions or ideas. The white space may represent clarity, purity, or a blank slate, while the red diagonal line could symbolize passion, anger, or a significant change that disrupts the calmness of the white background.

The direction of the line from top left to bottom right might suggest a journey or progression, possibly indicating that you are moving from a place of innocence or peace (top left) towards a more intense or challenging situation (bottom right). This could reflect a personal struggle or transformation you are experiencing in your waking life.

Consider how you felt during the dream and any specific associations you have with the colors or the line itself. This could provide further insight into what this dream may be trying to convey about your emotions or current life situation. If you're facing a challenge, it might be a sign to confront it rather than avoiding it.